A logo doesn't need to embody your entire brand, but rather be the shorthand to the way people feel about your brand.
A brand logo is the most valuable asset for any business.
Know Peretz Rosenbaum? He was the person behind the IBM logo, the old UPS logo, and many other corporate identities.
Logo Design comes under Graphic Design which influences the business and marketing of your product. By using signature colors in their logos, Starbucks, Coca-cola has become what they are today.